What I'm wondering, is if Ki Society Aikido, CAN Be used as a Self Defence. One site tells me "Placing emphasis on Ai-KI-DO with Ki at the center of techniques. It's a very soft and relaxed style."

There are two short answers; both coming from different directions.

"(A) No, Ki-Aikido is not useful for defence. (B)Yes, Ki-Aikido is extremely useful for defence."

This answer is not a discrepancy; which answer applies for you depends solely on your attitude/approach/outlook. You see, people often take martial arts for their 'defence/fighting' aspect, and frequently overlook the deeper aspects of what they're doing.
Let me elaborate: Saying this style or that style is better in a fight/defensive situation is a bit like saying Swiss is better than Cheddar on your sandwich - it all comes down to personal preference/learning style. People point to techniques seen in - for example, Shotokan Karate, or Wing Chung Gung Fu, and say "Hey, these are really cool, nifty, dangerous moves - this is a good fighting style."
Many of Aikido's (and particularly Ki-Aikido's) detractors think along these lines - the techniques determine the effectiveness.

The thing is, the techniques themselves are secondary to the art - they're teaching tools; not the art itself. If your concern is defence; what saves you on the street - the real, live, hairy street; not the simplistic cardboard cutout most think about - is not a nifty kokyu-nage or kote-oroshi, it's what the techniques teach. Balance, stability, awareness, co-ordination, relaxation under extreme stress etc. are what I'm talking about here.

The simple fact is, it isn't the art that makes a difference in a defensive situation, it's the person who's defending him/herself. That person needs to keep his head - both literally and figuratively in this case - and respond/react in an intelligent, effective and disciplined manner. Almost any style - providing it is taught with care and concientiousness - will allow you to learn to control your mind and body to a sufficient extent to defend yourself; assuming that option is presented to you. (Often, people curious about the Martial Arts ask me "What's the best fighting style?" I tell them "Yoga" and watch their faces. Cracks me up every time. Heh heh heh )

So that's the 'yes' part. In a nutshell, Ki-Aikido is a superb style for learning mind/body co-ordination and effective movement. Now for the "no" part.

All the above being said, I'm gonna throw in a major caveat concerning the defensive side of aikido - unless you've goat a really good instructor who directly addresses defence; chances are any attempt to 'use' aikido in a defensive situation is gonna get you splattered faster than a bug on a windshield; simply because the reality of defence is radically different from what is commonly taught in the dojo.

That is not a condemnation; rather an aspect of the confusion people tend to have between a 'self-defence' art and a 'defensive' art. Aikido is a defensive art - that is, it had few structures for attack, and its orietation is directed towards defensive principles. It is not a 'self-defence' art - it's far deeper and more subtle than that - re-read the 'yes' argument. The thing is, as deep as it is, it doesn't directly address the specific needs and goals required in a genuine defensive encounter; nor does it discuss the specific anatomy of modern-day real-world violence.

For example; the vast majority of the encounters I've been forced to endure either in the line of duty or otherwise have taken place in cramped confines, with obstacles and debris underfoot; frequently surrounded by bystanders who will take sides. Weapons are common as well, and one-on-one situations are very rare; three attackers being the most frequent. The most common factor however was that almost without exception, these encounters were all ambushes - violence launched in attempted surprise; from the oblique angle or from the blindside.

Note - I'm not talking barfights or schoolyard rumbles here; though those can and do turn deadly. I'm talking real violence; where someone wanted something - payback, gratification, money, or my client's ass - and was willing to go to extremes to get it. Figts are easy enough to avoid - don't fight. Assaults are sommat else entirely. This sort of violence Aikido does not train you for; since it doesn't exist within the art's focus. (Nor, for that matter, does it exist in the vast majority of other traditional MAs - that's not what the MA's about.) This is where specific instructors come in. There are many, many skilled instructors - many of whom are on Aikiweb and you will certainly hear from - that do understand the defensive complexity of real-world violence and do their utmost to prepare their students for that aspect. The best also train them hard to ensure students understand how to not have to use their physical aikido - IOW, to be able to avoid a defensive situation before it occurs.

One other thing - keep in mind that the 'defensive' aspect, while important, is a very small part of a much larger picture called Aikido. The defence is - or should be - there; but the value of Aikido manifests itself greater in terms of personal confidence, health, awareness of self and surround, discipline, and grace - both uses of the word. There is also the cameraderie and sheer joy of learning in a good dojo to consider. Aikido is far, far greater than simple self defence.

This is long and I'm tired - I hope I've been able to help in a small way to answer your question.